Colloidal and biological materials

The majority of the research is focused on colloidal and biological materials. In several textbooks [86,101,136,187] the related methods are elaborated. Recent developments are considered in a review of Svergun and Koch [188],... 

Typical Electrokinetic Parameters of Colloidal and Biological Materials... 

Phase-separation phenomena are commonly observed in various kinds of condensed matter, including metals, semiconductors, simple liquids, and complex fluids such as polymers, surfactants, colloids, and biological materials. The study of these processes of pattern evolution is very important for both engineering applications and basic understanding of nonequilibrium dynamics of pattern formation [1]. Phase separation in each material group of... 

The processes where porous membranes find their main applications are pressure-driven ones, such as microfiltration, ultrafiltration and nanofiltration. These processes are also especially interesting due to their wide range of practical applications. They can be used for the processing of fine particles, colloids and biological materials such as protein precipitates and microorganisms [3]. Membranes used are commonly polymeric materials but innovative development has been made in the fields of ceramic and inorganic membranes. 

Applications of Dielectrophoresis Over the past 20 years the use of DEP has grown rapidly to a point at which it is in use for biological, colloidal, and mineral materials studies and handfing. The effects of nonuniform elec tric fields are used for handling particulate matter far more often than is usually recognized. This includes the... 

Plutonium solubility in marine and natural waters is limited by the formation of Pu(OH)4(am) (for amorphous) or Pu02(c) (for crystalline). The K q of these species is difficult to measure, in part due to the problems of the polymer formation. A measured value for Pu(OH)4(am) is log = -56. This value puts a limit on the amoimt of plutonium present, even if Pu(V) or Pu(IV) are the more stable states in the solution phase. Moreover, hydrolyzed Pu(IV) sorbs on colloidal and suspended material, both inorganic and biological. 

The diversity of reactions which actinides can undergo in natural waters is pres ted schematically in Figure 22.9. Complexation by anions such as hydroxide, carbonate, phosphate, humates, etc. determine the species in solution. Sorption to colloids and suspended material increases the actinide concentration in the water while precipitation of hydroxides, phosphates, carbonates, and/or sorption to mineral and biological material limit the amount in the solution phase. 

Zhou, C., Qi, K., Wooley, K.L., Walker, A.V. (2008) Time-of-flight secondary ion mass spectrometry, fluorescence microscopy and scanning electron microscopy combined tools for monitoring the process of pattering and layer-by-layer assembly of synthetic and biological materials. Colloids Surf. B Biointerfaces, 65(1), 85-91. 

These are the materials which humans frequently encotmter. If one restricts the discussion, as in this book, to those common materials which occur either naturally or as the result of manufacturing processes as colloids, the list becomes very much shorter. Even with this shorter list, there are relatively few minerals whose surface thermodynamic properties have been determined. This reflects the fact that the underlying theory of surface thermodynamic components is relatively new and there are presently few researchers active in studying the properties of minerals as opposed to polymers and biological materials, for example. 

A lot of natural as well as technological objects of analytical control are colloidal systems, i.e. human blood, biological liquids, sol and suspension forming in different technological processes (ore-dressing, electrochemical deposition, catalysis and other), food, paint-and-lacquer materials, sewage water and other. 

What we have covered in this chapter barely scratches the surface of a vast area of applications of colloidal phenomena in chemical and materials processing industries and in environmental and other operations. There are many fundamental, as well as practical, problems in the above topics (especially ones involving polymers, polyelectrolytes, and polymer-colloid and polymer-surfactant mixtures) that are currently areas of active research in engineering, chemistry, physics, and biology. Some of the references cited at the end of this chapter contain good reviews of topics that are extensions of what we have covered in this chapter (see, e.g., Elimelech et al. 1995, Hirtzel and Rajagopalan 1985, Israelachvili 1991, Gregory 1989, and O Melia 1990). 

Since physical chemistry is the point of departure for this presentation, the undergraduate chemistry major is the model reader toward whom the book is addressed. This in no way implies that these are the only students who will study the material contained herein. Students majoring in engineering, biology, physics, materials science, and so on, at both the undergraduate and graduate levels will find aspects of this subject highly useful. The interdisciplinary nature of colloid and surface chemistry is another aspect of these subjects that contributes to their relevance in today s curricula. 

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